Katayama Masafumi, Kataoka Ayusa, Fukuda Tomokazu, Onuma Manabu
Biodiversity Division, National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan.
Ayutomo Animal Hospital, Kitakyusyu, Fukuoka, Japan.
PLoS One. 2025 Sep 25;20(9):e0332954. doi: 10.1371/journal.pone.0332954. eCollection 2025.
The Iriomote wild cat is endemic to Iriomote Island. The total population is only 100 cats. These cats are thus listed as critically endangered on the IUCN Red List. Infectious disease is a risk factor for further reducing the Iriomote wild cat population. RIG-I, MDA5 and TLR3 are important sensors that recognize host viral defense responses. IL6, Mx, and OAS are downstream genes of RIG-I and MDA5. Polyinosinic:polycytidylic acid (poly(I:C)) stimulates the RIG-I, MDA5 and TLR3 in many animals. In this study, we thus tried to compare RIG-I, MDA5, and TLR3 responses after exposure to the poly(I:C) in domestic cat- and Iriomote wild-cat-derived fibroblasts. This study also compared the expression of downstream gene (IL6, Mx, and OAS) of RIG-I and MDA5. This study analyzed the genes expressions of domestic cat- and Iriomote wild-cat-derived fibroblasts after exposure the poly(I:C), using real-time PCR and RNA-seq. In addition to these genes expression, this study compared the gene sequence of RIG-I and MDA5 between domestic cat and Iriomote wild cat with information of public database. RIG-I and MDA5 levels were increased in both domestic cat- and Iriomote cat-derived fibroblasts after poly(I:C) exposure, while TLR3 expression did not change dramatically after poly(I:C) exposure. A comprehensive gene expression analysis revealed that molecular responses of fibroblasts derived from domestic cats and those derived from Iriomote wild cats to poly(I:C) exposure were similar. Furthermore, RIG-I and MDA5 sequences are similar between domestic and Iriomote wild cat. Our results suggested that poly(I:C) mainly stimulates RIG-I and MDA5 among the three genes (RIG-I, MDA5 and TLR3) examined in this study, and the RIG-I and MDA5 mediated molecular responses to poly(I:C) exposure are similar in domestic and Iriomote wild cats fibroblasts. To the best of our knowledge, this is the first study to compare the RIG-I and MDA5 responses of Iriomote wild cats and domestic cats after poly(I:C) exposure. This study provides valuable insights into the cellular response mediated by RIG-I and MDA5 in the Iriomote wild cat.
西表山猫是西表岛特有的物种。其种群总数仅100只。因此，这些猫在世界自然保护联盟红色名录中被列为极度濒危物种。传染病是进一步减少西表山猫种群数量的一个风险因素。视黄酸诱导基因I（RIG-I）、黑色素瘤分化相关基因5（MDA5）和Toll样受体3（TLR3）是识别宿主病毒防御反应的重要传感器。白细胞介素6（IL6）、Mx蛋白和2'-5'-寡腺苷酸合成酶（OAS）是RIG-I和MDA5的下游基因。聚肌苷酸:聚胞苷酸（poly(I:C)）可刺激许多动物体内的RIG-I、MDA5和TLR3。因此，在本研究中，我们试图比较家猫和西表山猫来源的成纤维细胞在暴露于poly(I:C)后RIG-I、MDA5和TLR3的反应。本研究还比较了RIG-I和MDA5下游基因（IL6、Mx和OAS）的表达情况。本研究使用实时定量聚合酶链反应（real-time PCR）和RNA测序分析了家猫和西表山猫来源的成纤维细胞在暴露于poly(I:C)后的基因表达。除了这些基因表达外，本研究还利用公共数据库信息比较了家猫和西表山猫之间RIG-I和MDA5的基因序列。在暴露于poly(I:C)后，家猫和西表山猫来源的成纤维细胞中RIG-I和MDA5的水平均升高，而TLR3的表达在暴露于poly(I:C)后没有显著变化。全面的基因表达分析表明，家猫来源的成纤维细胞和西表山猫来源的成纤维细胞对poly(I:C)暴露的分子反应相似。此外，家猫和西表山猫之间RIG-I和MDA5的序列相似。我们的结果表明，在本研究检测的三个基因（RIG-I、MDA5和TLR3）中，poly(I:C)主要刺激RIG-I和MDA5，并且RIG-I和MDA5介导的对poly(I:C)暴露的分子反应在家猫和西表山猫的成纤维细胞中相似。据我们所知，这是第一项比较西表山猫和家猫在暴露于poly(I:C)后RIG-I和MDA5反应的研究。本研究为西表山猫中由RIG-I和MDA5介导的细胞反应提供了有价值的见解。
